Cannon pinion



April 1931. E. L. FENTERMAKER CANNON PINION Filed Dec. 15, 1927 gwuv/vwoz Emanudlfnstermaler Patented Apr. 7, 1931 EMANUEL L. FENSTERMAKEB, OF LANCASTER, PENNSYLVANIA CANNON PINION Application filed December 13, 1927.

My invention relates to cannon pinions used in time keeping instruments, such as watches, clocks and the like.

Heretofore various types of cannon pinions U have been used but considerable diiiiculty has 10, either break when being applied or removed,

or the stress required for such operations would distort the metal in such a manner that it would not spring back into place.

It is an object of the invention to provide a cannon pinion which is non-easily breakable, adaptable to staffs of different sizes, and one which may be easily applied or removed from its staff without injury, insuring proper friction upon the staff at all times, all as will be hereinafter more particularly described and claimed.

Referring to the accompanying drawings which are made a part hereof and on which similar reference characters indicate similar parts,

Figure 1 is a side elevation of my improved cannon pinion mounted on a staff,

Figure 2, a central longitudinal section on the line 22 of Fig. 1,

Figure 3, a transverse section on line 33 of Fig. 1, and

Figure 4, a side elevation illustrating a modified form of cannon pinion.

In the drawings reference character 10 indicates a center stafi' of conventional construction upon which is mounted a cannon pinion comprising a sleeve 11 having spaced external enlargements 12 and 13 which form bearings for the hour wheel, not shown, and an intermediate smaller external cylindrical portion 1 1. The inner surface 15 of the sleeve is of uniform size and is provided with a protuberance 16 formed adjacent the middle of the same centrally of the reduced intermediate portion 14. The protuberance 16 is adapted to fit into a depression 17 in the staff 10 and when the pinion is applied on the staff such protuberance rides over the end of the staff and snaps into the depression 17 where it remains holding the parts frictionally in E-crial No. 239,801.

fixed relation until the pinion is removed. In order to allow flexibility sufficient to prevent the protuberance from being sheared off upon application of the pinion to the staff and also in order that the metal about the protuberance will not be strained or distorted so that it will not return to normal position, I provide a longitudinal slot 18 in the sleeve 11 beside the protuberance 16. The longitudinal slot permits the desired amount of flexibility and does not reduce the strength of the pinion but on the contrary enhances its serviceability and permits the sleeve to be pinched together to fit tightly on a smaller staff.

In Fig. 4 I have shown a cannon pinion having a pair of slots 18, one on each side of the protuberance. 16. This construction increases the flexibility and does not materially weaken the pinion. The slots 18 are shown extending longitudinally since the greater the length of the slot the greater is the flexibility provided, however, where less flexibility is desired the slots may be disposed at an angle to that shown.

In manufacturing the protuberance is formed on the inner surface of the sleeve by punching from the exterior with a blunt tool similar to a center punch. This operation is performed prior to the final turning down of the pinion. The final turning down removes all impression from the outer surface of the pinion.

It will be obvious to those skilled in the art, that various changes may be made in my device without deoarting from the spirit of the invention, and I, therefore, do not limit myself to what is shown in the drawings and described in the specification, but only as set forth in the appended claims.

Having thus fuily described my said invention, what I claim as new and desire to secure by Letters Patent, is:

1. A pinion for a shaft having a shouldered portion and a cut-away portion sloping and increasing in depth toward the shoulder, said pinion comprising a sleeve having enlarged ends adapted to serve as bearings, said sleeve being reduced in thickness intermediate the enlarged ends and having a longitudinal slot terminating short of the ends, and a projection on 'the interior of the reduced portion, said projection engaging the shaft at the sloping, cut-away portion so as to cause the pinion to tend toward the shouldered portion, substantially as set forth.

2. In a cannon pinion for timepieces, the

combination with an arbor, a shoulder on said arbor, a tapered portion on said arbor taper= ing towards said shoulder, of a pinion adapted to bear against saidshoulder, a bearing sleeve formed integral with said pinion and having its central portion thinner than its end portions, said thin portion having a longitudinal slot therein, and a projection on the inside of said thin portion adjacent one side of said slot, said projection being adapted to bear on said taper to form a friction clutch ther with, substantially as set forth.

" 3. In a cannon pinion for tiniepieces'the combination withan arbor, a shoulder on said: arbor, a tapered portion on said arbor taperng towards said shoulder, of a pinion adapted to bear against said shoulder, a hearing sleeve formed integral with said pinion and havingitscentral port-ion thinner than its end portions, a semispherical projection I within said thin portion, said thin portion having'a longitudinal slot therein adjacent said projection to allow expansion or 'contraction of said thin portion, said projection being adapted tohold said pinion against said shoulder'by coacting with the inclined surface of said taper,'substant1ally as set forth. 7

In witness whereof, I have hereunto'set myhand Lancaster, Pennsylvania this ninth day of'Deceinber, A,-

nineteen hundred and twenty-sevenj EMANUEL L. FnNsTnR aK a. 

